A crayon apple tree['The Interactive Palette' is a biweekly GameSetWatch-exclusive column by Gregory Weir that examines the tools and techniques of the digital games trade with a focus on games as art, using a single game as an example. This time - a look at failure-friendly gameplay in Crayon Physics Deluxe.]

One of the basic issues of video game design is that of the skill challenge. Early arcade games like Pac-Man and Space Invaders are gauntlets to be run, where a high score is the goal and failure is all-but-guaranteed. Indeed, the developers didn't even expect players to be able to succeed as well as they have.

Pac-Man crashes on the "kill screen" at level 255, and Space Invaders's score counter rolls over to zero after 9,990. These early games were descendents of carnival amusements and pinball; they provided ways for players to test their skill against the machine and against each other.

Games are no longer simply about skill, but the idea of the skill challenge remains. Many games, such as Super Mario Galaxy, still record "lives," even though the player is able to save and continue indefinitely. This apparent need to challenge the player often leads to what Shamus Young calls "do it again, stupid." The player will be assigned a particularly difficult task, where failure simply means that she must keep trying, over and over, until the task is accomplished. It's as if the punishment for failure is lost time and frustration.

Difficulty has an important role in video game design. It allows the player to empathize with the efforts of the player character, it helps to pace the game, and it provides the player with a feeling of accomplishment (provided the player doesn't just give up in frustration).

However, there is a difference between challenge and punishment for failure. The 2008 Prince of Persia was widely criticized for being too easy, in part because it doesn't punish the player enough for failing at a jump or a boss fight. However, this has little effect on how difficult the game is; it just means that the cost of failure is reduced.

Petri Purho's recent game Crayon Physics Deluxe presents an almost frustration-free experience by being failure-friendly. It presents true challenges, but does not severely punish the player for failing at them. Indeed, the failure experience not only teaches the player how to do better, but it is fun in its own right.

A crayon castleDynamic Friction

For the purposes of this article, I'll break up the vague term "difficulty" into two: challenge and punishment. A challenging game, in this definition, is one which is hard because the tasks involved require a high level of skill, ability, or cleverness. A punishing game is one which provides a high cost of failure. Most old LucasArts adventure games like Monkey Island and Full Throttle provide challenging but unpunishing experiences.

Figuring out the puzzles requires a great deal of cleverness, but there is no way to die or lose progress in the game, so the game doesn't punish failure beyond refusing to progress the story until challenges are met. One can just as easily imagine a game which is unchallenging but punishing: the individual tasks are easy, but a single mistake would send the player back to the beginning of the game.

Overcoming challenge is much of the fun of video games for most players. Overcoming obstacles and proving one's prowess is entertaining and feels good. A game without challenge is one in which the conflict does not affect the player, only the characters. Different players desire different amounts of challenge, but most players want to achieve some amount of success over difficulty.

Punishment, on the other hand, primarily generates frustration and wasted time. It's difficult to come up with a way that punishment improves the game experience, but here's an attempt: punishment provides the negative reinforcement that makes success feel more "real." Without the knowledge of a negative consequence, it can feel like the player's achievement was not really hers, or was inevitable given enough time to attempt it.

As a player, I prefer gameplay to be reasonably challenging and minimally punishing. Crayon Physics Deluxe achieves this goal. It presents a series of puzzles which must be solved by drawing shapes to get a red ball to a gold star. These puzzles are often quite challenging: one of Purho's favorite tricks is to place the goal higher than the ball, forcing players to work against gravity.

However, the game provides the player with very little punishment. If the ball falls off of the screen, it immediately reappears at its starting location. This allows the player to restart the puzzle immediately with no lost time, and reinforces the urge to try just one more time.

The nature of Crayon Physics's game mechanics reinforce this balance. The game is a robust simulation, which means that any solution that should work does work. Many puzzles clearly have an intended solution, but players are free to experiment and create a convoluted or brute-force approach. Creativity is encouraged by rewarding it, instead of being discouraged due to there only being a single solution. Even techniques that aren't taught until the end of the game can be used in the first level, providing an additional challenge: solve puzzles in multiple ways.

A crayon personApplied Forces

By examining Crayon Physics Deluxe, we can see how video games can be challenging without being frustrating. By minimizing punishment, games can evoke all of the good aspects of challenge — the feeling of accomplishment, the sympathy with the player character, and the pacing challenges provide — without making the player feel inadequate or wasting the player's time. This requires three things: challenges must be legitimate, recovery must be quick, and creativity must be encouraged.

Legitimate challenge is, sadly, less common than it should be. Games should be challenging because they test player skill, not because they present arbitrary obstacles. A fork in the road with one path leading to instant death and the other leading to success is only legitimate if enough clues are provided that the player can reasonably determine which path is the right one. In games where failure is severely punished, this may feel challenging, but the removal of the punishment reveals that this sort of thing is just an artificial way of extending gameplay.

It is far better to present a challenge that requires the player to be clever or quick or precise than to present one that requires she be lucky. Likewise, sudden unexpected twists like enemies ambushing the player should be fair; if the only way for a player to succeed is to "predict the future" and anticipate the surprise that made her fail the first time, that's not challenge. It's the developer punishing the player for not possessing precognition.

Quick recovery from failure minimizes the amount of time wasted by waiting or redoing already-beaten parts of the game. A player who has to replay the first half of a level or wait through a lengthy loading screen ten times will become bored, and boredom is not what any developer should be aiming for. Quicksaving can help with this, as the player can return to her saved game ten seconds earlier. Far better, however, is a system of frequent autosave checkpoints, so that the player doesn't have to tap F6 every fifteen seconds. Players should not be forced to repeat content.

There are two slight exceptions to this rule. The first is when part of the challenge is to bypass several obstacles in sequence. In this case, the sequence should differ enough each time or be complex enough that the player is not bored or frustrated by repeating it. The second exception is in multiplayer games such as Counter-Strike, where a "time out" period after death grants an advantage to successful players. In this case, moderation is key to avoid putting players to sleep.

The last requirement of effective challenge is to encourage player creativity. A challenge which can only be completed one way is an exercise in reading the developer's mind. The more difficult an obstacle is, the more the game should allow the player to try different tactics and approaches to succeeding at it. This may require specifically engineering alternate paths, or it may just call for a richer simulation that allows for emergent solutions. The possibility of creativity allows the player to learn from failure and to have a different experience each time she attempts a challenge.

Crayon Physics Deluxe is, of course, a puzzle-solving game, and is a different animal than the majority of monster-killing games. However, the techniques it uses to manage difficulty can be applied to any genre. By setting an appropriate level of challenge but minimizing the frustration of failure, games can be more rewarding and better create the sensation of flow. Failure-friendly design allows players to have more fun with less wasted time and pulled hair.

[Gregory Weir is a writer, game developer (The Majesty Of Colors), and software programmer. He maintains Ludus Novus, a podcast and accompanying blog dedicated to the art of interaction. He can be reached at Gregory.Weir@gmail.com.]